Winding machine for filament-wound structures



July 18, 1967 w. E. PONEMON 3,331,722

WINDING MACHINE FOR FILAMENT-WOUND STRUCTURES Filed April 25, 1963 FIG. 3

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ATTORNEY United States Patent 3,331,722 WINDING MACHINE FOR FlLAMENT-WOUND STRUCTURES Warren E. Ponemon, Syosset, N.Y., assignor to Koppers Company, Inc., a corporation of Delaware Filed Apr. 25, 1963, Ser. No. 275,690 8 Claims. (Cl. 156-425) The present invention relates to apparatus for producing filament-wound hollow bodies and more particularly to improved means for winding filaments upon a mandrel provided with rounded end portions.

Laminated structures formed of resin-impregnated Fiberglas, or the like, have gained wide use due to the favorable characteristics of light weight, high tensile strength and freedom from corrosion, replacing metal structures in many cases. Structures, such as pipes, conduits, or similar hollow cylindrical structures, are well known in the art and various methods are currently in use for producing such structures in quantity at relatively low cost. However, considerable difficulty and complexity have been encountered in forming some filament-wound hollow bodies such as tanks or other containers. Such structures are coming into wider acceptance in fields where extremes in environmental conditions are encountered, wherein Fiberglas lamination shows high performance characteristics. Thus, Fiberglas containers have found utility in such diverse fields as rocket casings and storage receptacles generally, where tensile strength combined with light weight are of critical importance. Rapid, economical fabrication of sea-led members thus becomes of increasing importance. However, devices suitable for fabricating open piping cannot be employed since the closure member involves application of the filament at a very low helix angle instead of the conventional helix angle which varies from 30 to almost 90 degrees.

A further problem in fabricating enclosed vessels of the above type is that a considerable time is expended traversing the end portions of the mandrel. It will be appreciated that constant tension must be maintained to hold the filament loops tightly on the end caps to form an integrated structure when the winding is completed. The rigidity of the structure ultimately depends on the degree of filament tension and the resin binder employed, to resist internal and external pressures applied to the vessel. Considerable difiiculty has been encountered in applying such filaments to rounded or ellipsoid structures while maintaining filament tension, without undue dwell-time on the part of the feed element. For example, on a typical large pressure vessel Winding such as a rocket engine case of say, seventeen-foot length and a five-foot diameter, a total of 360 degrees of mandrel rotation is required for the feed eye to traverse both ends, whereas only a total of 250 degrees of mandrel rotation is required for the eye to make the complete pass from the left tangent point to the right tangent point and from the right tangent point to the left tangent point. It will thus be apparent that more time is needed for going around the end portions of the mandrel on a conventional helix winding machine than is consumed in winding the cylindrical length of the case. Up to the present time, winding pressure vessels of this type has been a time-consuming complex phase of the art. For example, it took forty-eight hours to wind a seventeenfoot vessel using prior devices. Thus a saving in time is of great significance.

It is therefore a primary object of the present invention to provide an improved filament-winding machine wherein minimal time is required for traversing the ends of a pressure vessel of the type above described.

It is a further object of the present invention to provide means for winding Fiberglas filament or the like upon a mandrel at a very low helix angle down to and including zero degrees, where desired.

It is still a further object of the present invention to provide means for maintaining constant tension upon the filament fibers when winding these around the end domes of a mandrel.

It is an additional object of the present invention to provide a device for positioning an end wrap of a mandrel wherein the feed device traverses a minimal distance relative to the length of the mandrel in contradistinction to conventional winding devices which require a traverse for a considerable distance beyond the mandrel or considerable dwell-time in order to provide the end wrap.

These and other objects and advantages of the present invention will be pointed out with particularity or will be apparent from the following description together with the figures appended thereto in which:

FIG. 1 is a plan view of a device of the present invention.

FIG. 2 is an end elevation taken along line 2-2 of FIG. 1.

FIG. 3 is a side elevation taken along line 3-3 of FIG. 1.

FIG. 4 is a diagrammatic view illustrating the path of the filament delivery eye in plan view.

FIG. 5 is a diagrammatic view illustrating the path of the filament delivery eye in an end view.

FIG. 6 is a diagrammatic view illustrating the path of the filament delivery eye in a side view.

FIG. 7 is a typical top plan view of a single circuit applied to a mandrel.

FIG. 8 is a plan view of a single circuit of a zero angle winding applied to a mandrel.

Referring now more particularly to the drawings, there is shown in FIG. 1 a plan view of the present invention characterized generally by the numeral 10 wherein drive means 12 imparts constant rotational speed to shaft 14. Mandrel 16, having rounded end portions 18-18, is rotatably supported on shaft 14 in a fixed axial position. Feed mechanism 20 is in the nature of an overhead traveling crane device provided with its own drive means synchronized to the mandrel rotation and adapted to give the feed mechanism three planes of motion relative to the mandrel, and is shown here diagrammatically by cylinder and piston 22. Drive mechanism 22, plus similar mechanisms 24 and 26, provide a forward and aft motion (x axis, FIG. 1), a transverse motion at right angles to this (y axis, FIG. 1), and a vertical up or down motion (z axis, FIG. 3), respectively. By the proper control of the relative motions, the device of the present invention can be programmed with any three-dimensional path desired. However, for purposes of illustration, a simple figure-eight motion will be described hereinbelow.

Feed mechanism 20 mounts feed eye 28 which positions filament 30, fed by spools 32, against the mandrel 16. Resin-impregnating means 34 are disposed proximate to eye 28, as shown in FIG. 3. However, if preimpregnated material is used, impregnating means 34 could be eliminated.

FIGS. 4-6 show schematically the relative motion of the mandrel and the feed mechanism with respect to each other. As viewed in the plan view of FIG. 4 and the side elevation of FIG. 6, the feed mechanism 20 traverses a path from left to right. While so doing, the feed mechanism deposits a strand on the top of the mandrel in the area between the end portions 1848'. Since the mandrel is being rotated in a counterclockwise direction (FIG. 5) and the feed eye is moving perpendicular to the longitudinal axis of the mandrel, while at the same time being carried both parallel and transverse to the longitudinal mandrel axis by the feed mechanism 20, the entire body of the mandrel will be wrapped. As a result of the combination of aforementioned concurrent relative motions, feed mechanism will pass both end portions 13-18 traveling in a direction opposite to the mandrel rotation. This will efiect an extremely rapid winding at critical points that were, in the prior art, disproportionately time-consuming. This has the effect of bringing the feed mechanism 20, at the terminal portions of the wrapping cycle, in position to move counter to the direction of rotation of the mandrel, namely, at points 1 and 4, whereby rapid traverse of the endportions of the mandrel can be effected. The basic movement of the filament delivery eye when observed from a position above the machine and looking down, will be a figure-eight, as shown in FIG. 4, with the cross-over point on the center line a-b of the mandrel'being wound. As seen from the end position, FIG. 5, the motion of the delivery eye is a traverse of the end section from left to right substantially through the center of the mandrel, namely, from point 4 to 5.

It is theusual practice to employ a plaster mandrel against which are positioned flanged end fittings provided with an opening. The winding is laid over the end fittings with each circuit offset from the prior circuit,- as is well known in the art. The mandrel, be it of plaster or other disposable material, is broken up and removed through the end fitting 48 (FIG. 7). In some instances, a hollow mandrel, say a liner of stainless steel or other suitable material, is provided. The liner can then be left inside the windings. In the latter case, the end members may be integral with the liner.

After passing point 2 and up to point 4, the path of p the eye is counterclockwise around the mandrel back to the horizontal center line.

When viewed from the side position, FIG. 6, the feed eye 28 would appear to go into the plane of the paper ou the right side of the mandrel, progress along the side of the mandrel coming up over the mandrel at itsmidpoint 3 and then down to the horizontal center line at point 1 on the left side. It would then proceed into the plane of the paper to a position in the rear of the mandrel and then cross over behind the mandrel from left to right, come out of the paper crossing again in the center 3, and on down again on the front left hand side of the mandrel. After each winding the mandrel is angularly offset with relation to the prior winding, as is well known in the art.

A particularly noteworthy feature of the present invention is that the Winding around the ends, which previously took a great deal of time, is now accomplished rapidly because the feed-eye takes a path such that the velocity component is opposite to that of the mandrel.

A single turn '50 typical of the resultant winding is shown in FIG. 7. It should also be noted that winding 52 with Zero helix angle, such as shown in FIG. 8, may A readily be provided for by letting the eye have the same component of rotational velocity as the mandrel. In FIG.

7 8 only a single turn is shown for purposes of clarity. As

such, there will be no relative motion between the mandrel and the eye in the rotational direction and in this way, the helix angle would 'be zero. The helix angle is described as the. angle that the filament makes with the horizontal center line passing through the mandrel. Synchronization between the feed mechanism and the rotational peed of the mandrel may be arranged by a mechanical cam device. However, it will be appreciated that a three-dimensional servo system may readily be substituted for this, with the system taking command signals from punch tape or a similar type of information device.

quired for the feed eye to traverse both ends, whereas only a total of 250 degrees of mandrel rotation was required for the eye to make the complete pass from left to right and from right to left. Thus, it becomes obvious that a conventional helical winding machine required more time to traverse the ends than it required for traversing the longitudinal body of the case. This is in contradistinction to the present device, where only a small fraction of the Winding cycleis spent in Winding the end portions. Fur-, thermore, the conventional helical winding machine traverses a considerable distance beyond the mandrel, or dwells, or speeds up the mandrel, in order to provide the end wrap. In the figure-eight machine, hereinabove described, however, it is not necessary for the device to travel beyond the length of the mandrel'as the same effect is accomplished by cross-feeding the eye around the end portions of the mandrel, as hereinabove described.

Reference has been made to a filament winding. It'is envisioned thata plurality of filaments may be employed in a bundle. If desired, the bundle may be laid down as a ribbon or band. 7

. Presently glass is the preferred filament. However, other filamentary or even woven materials can be used to meet particular requirements.

The choice of binder will depend on the intended application. For rocket motors and the like, epoxy resin are currently preferred.

There has been disclosed heretofore the best embodiment of the invention presently contemplated and it is to be understood that various changes and modifications may 'be made by those skilled in. the art without depart ing from the spirit of the invention.

What is claimed is: 1. An apparatus for producing resin bonded filamentwound hollow bodies having end portions comprising:

(a) a frame member; (b) .a mandrel rotatably mounted in said frame member; (c) drive means to rotate said mandrel about its own longitudinal axis;

('d) filament feed-eye means positioned proximate said traveling parallel to and above the longitudinal axis of said mandrel, and said feed-eye means is carried by said crane. a

4. An apparatus for producing resin-impregnated hollow bodies having rounded end portions comprising:

(a) frame member; 7 i i (b) a rounded end mandrel rotatably mounted in said frame member; (c) drive means to rotate said mandrel about its own longitudinal axis; (d) a filament supply source for providing filaments to be wound on said mandrel; (e) filament impregnating means adapted to apply a resin coating to said filament prior to winding said bundle on said mandrel;

and over the ends of said mandrelfand (g) means to guide said feed-eye along three mutually perpendicular axes atindependent rates.

5. Apparatus for producing filament wound pressure vessels comprising: (a) a frame; (b) a rotatable mandrel mounted in said frame; drive means for rotating said mandrel about an axis; (d) a filament source for providing filaments for winding on said mandrel; (e) filament impregnating means to apply a heat hardenable coating to said filaments; (f) a first support movably mounted to said frame; (g) first means for moving said first support in a first plane parallel to the axis of rotation of said mandrel; and (h) a second support movably mounted to said first support and movable therewith and carrying (i) means for guiding said impregnated filaments onto the surface of said mandrel as the same rotates, and (ii) second means for moving said second support and said guide means in a second plane perpendicular both to the axis of said mandrel and to said first plane, and (iii) third means for moving said guide means in a plane perpendicular to both said first and said second plane, whereby said filament is Wound quickly onto the end portons of said mandrel. 6. The invention of claim wherein: (a) the movement of said first and said second supports is reciprocating; and (b) said guide means is reciprocable.

7. The invention of claim 5 wherein:

(a) said first, second and third means are individual piston-cylinders.

8. Apparatus for producing filament wound pressure 5 vessels comprising:

References Cited UNITED STATES PATENTS 2,966,935 10/1957 Wiltshire 156-433 3,047,191 7/1962 Young 156-189 3,133,236 5/1964 McCauley 2427 3,174,388 3/1965 Gaubatz 156169 X EARL M. BERGERT, Primary Examiner.

J. P. MELOCHE. Examiner. 

1. AN APPARATUS FOR PRODUCING RESIN BONDED FILAMENTWOUND HOLLOW BODIES HAVING END PORTIONS COMPRISING: (A) A FRAME MEMBER; (B) A MANDREL ROTATABLY MOUNTED IN SAID FRAME MEMBER; (C) DRIVE MEANS TO ROTATE SAID MANDREL ABOUT ITS OWN LONGITUDINAL AXIS; (D) FILAMENT FEED-EYE MEANS POSITIONED PROXIMATE SAID MANDREL, SAID FEED-EYE MEANS BEING ADAPTED TO CONTINUOUSLY DEPOSIT A BUNDLE OF RESIN-IMPREGNATED FILAMENTS ALONG THE LENGTH AND OVER THE ENDS OF SAID MANDREL; AND (E) DRIVE MEANS FOR MOVING SAID FEED-EYE AT INDEPENDENT RATES ALONG EACH OF THREE MUTUALLY PERPENDICULAR AXES. 